Characterization of Fe–Cr Alloys for Reduced Operation Temperature SOFCs

✍ Scribed by T. Horita; Y. Xiong; K. Yamaji; N. Sakai; H. Yokokawa

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 557 KB
• Volume: 2
• Category: Article
• ISSN: 1615-6846
• DOI: 10.1002/fuce.200290018

✦ Synopsis

Abstract

Chemical stability of ferritic (Fe–Cr) alloy interconnect material was examined under anode gas atmospheres for use in solid oxide fuel cells (SOFCs). In H~2~–H~2~O and CH~4~–H~2~O atmospheres, oxide scale layers were formed on the alloy surface. The surface morphology of the alloy was varied with forming oxide scales at 1073 K for an extended annealing time. Secondary ion mass spectrometry (SIMS) was applied to analyze the distribution of major and minor elements as a function of depth. From surface to inner alloy, the following distribution was identified: Mn, Fe rich → Cr rich → Si rich → alloy bulk and Al~2~O~3~ inner oxides. The parabolic growth rate constants of oxide scales (k~p~) were calculated for each atmosphere as follows: 3.76 × 10^–6^ μm^2^s^–1^ for H~2~–H~2~O and 5.23  × 10^–6^ μm^2^s^–1^ for CH~4~–H~2~O. The growth rate constants were similar between these two atmospheres.